1. Field of the Invention
This invention relates to a dynamic stopping device for rail cars and in particular for use with tracks in classification yards to prevent run out of rail cars at the end of the classification tracks, due to lack of gradient or speed control in these particular tracks.
2. Description of the Related Art
A problem encountered in classification yards is the tendency of cars to “creep” or “run out” and thereby compromise the efficiency of the processes of the yard, and can even constitute a danger by leaving the track, fouling switches and other tracks in the process, if not effectively stopped. Run out occurs when the car's speed is not properly controlled by sufficient inclined gradients at the end of classification tracks, or due to the lack of retarder speed control. The cars can also be pushed out through the track due to the impact from other cars continuously coupling to the first cars in the train.
An early device is described in GB424517 (1935 to John Mitchell) for preventing cars from running backwards down an incline. A catch is pivoted in a sunken casing and is maintained in a projecting position to stop cars travelling in one direction but allowing cars or other vehicles from travelling in the opposite direction by virtue of the catch being displaceable by cars in the opposite direction. This arrangement is somewhat crude and will have limited, if any, use in classification yards, mainly because contact of a car wheel or axle with the catch may result in a violent impact.
Another prior art device is described in GB859757 (1961 to Hobbs et al) includes a similar catch or arm acting against a ram for stopping and checking individual rail vehicles such as mine cars.
It is an object of the present invention to provide a stop device which is not only useful for slowing down and stopping rail cars generally but has also particular utility in situations such as classification yards.